| Prefabricated drains are good vertical pathway in dealing with soft soil foundation such as slime, muddy soil, alluvial and aggradational soil etc. saturation viscidity soil and disorder heaping soil. with drainage consolidation. The time of consolidation can be shorten greatly. The act, design and construction equipment of the prefabricated drains are basically similar to sacked sand well in dealing with soft soil foundation, but the combined cost of former reduces 30% than that of the later, the construction speed of the former is faster than that of the later about 1/3. Prefabricated drains are banding composite framework with core board by piling out shaping in the middle. the core board is skeleton and pathway of plastic board, its cross-section is parallel cross and made up of 35 ribs and 34 arks.The width of the prefabricated drains is 100 mm and their thickness is from 3.5 to 6.0 mm. There is composite chemical fiber spin fabrics outside core board that can stop soil and act as a straining membrane.There are many soft soils as slime, muddy soil, alluvial and aggradational soil in the coastal area of south China, water content of these soft soils is heavy, compressibility is high, intensity is low and water permeability is bad with deeply buried in many situation. Because of the above characteristic, the subsidence and subsidence difference of the building will be large, the time of settlement will be much longer under the loading of the building itself. The normal using of the building will be impacted seriously. The drainage consolidation law can be used widely to reinforce those soft soil foundation, this method is proved to be effectual by a large number of project.The saturate soft soil can be drained and consolidated with the act of the pressurization and drainage system during the drainage consolidation. With this method majority subsidence of the soft soil is dispelled and the density and strength of the soft soil are improved. Drainage consolidation method consist of pressurization and drainage system. The way is the best method in treating slime, muddy soil, alluvial and aggradational soil etc. saturation viscidity clay and disorder heaping soil foundation.Its pressurization system is preloading earth and rock, the preloading load is the load of the building itself,unload need not be done after strengthening, then it will be economical in the construction cost and the construction period will be shorten. The drainage system consist of sand cushion layer and prefabricated drains.Drainage consolidation principle is following: with the top load soft soil is compressed and pore water is out along with prefabricated drains and horizontal sand cushion layer. The pore water pressure is down and correspondent effect stress is up, the quantity of the depletion is equal to the increment, with the pore water pressure turning to the effect strength, the soft soil is consolidated.Vacuum preloading draining with prefabricated drains, combined vacuum-surcharge draining with sacked sand well ,stack-load preloading draining with prefabricated drains and combined active and stationary draining consolidation method are used commonly in reinforcement of the soft soil foundation at present . The soft peat slime,silty clay and silt are the all soft soils of the road foundation in this project. water content of these soils is heavy, compressibility is high, intensity is low and water permeability is bad. According to this propety, the stack-load preloading draining with prefabricated drains can be applied in this project. In order to introduce and popularize this method applied in northeast China, through study on this project this method was adopted to reinforce soft soil road foundation.Although stack-load preloading draining with prefabricated drains has been widely used in coastland of south China, there is no precedent in severe cold area of northeast China. So this study is important to the supplementary reinforcement of soft soil foundation in northeast China.Synthetic research on the project... |
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